SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f17a8e58e468b305766755f324b22142f3df1690fb47658d510468282f06c20e' 
  AND token = 'Tz9Ny/tDzt0Cyx0A8hcieChGfsLIVLMBxMfBDyNSkfg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}